Compressor configuration system and method

ABSTRACT

A cooling system includes a compressor rack, a controller, a gateway, and a system master. The compressor rack includes a plurality of compressors. A controller is dedicated to each compressor and includes a memory storing configuration data for the compressor. A gateway is in communication with each controller and allows the system master to command the controller to send the configuration data to the system master, whereby the system master stores a copy of the configuration data for each compressor.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation of U.S. patent applicationSer. No. 09/977,552 filed on Oct. 15, 2001, which is a division of U.S.patent application Ser. No. 09/515,802 filed on Feb. 29, 2000 (now U.S.Pat. No. 6,302,654). The disclosures of the above applications areincorporated herein by reference.

FIELD OF THE INVENTION

[0002] The present invention relates to the control and protection ofcompressors. More particularly, the present invention relates to acompressor control and protection system which combines compressortemperature control, phase protection, vibration protection, oil levelcontrol and protection, pressure sensing and pulse width modulationcontrol.

BACKGROUND AND SUMMARY OF THE INVENTION

[0003] Scroll type machines are becoming more and more popular for useas compressors in both refrigeration as well as air conditioningapplications due primarily to their capability of extremely efficientoperation. Generally, these machines incorporate a pair of intermeshedspiral wraps, one of which is caused to orbit relative to the other soas to define one or more moving chambers which progressively decrease insize as the travel from an outer suction port toward a center dischargeport. The means for causing the orbiting of one of the scroll members isin many cases an electrical motor. The electric motor operates to drivethe one scroll member via a suitable drive shaft affixed to the motorrotor. In a hermetic compressor, the bottom of the hermetic shellnormally contains an oil sump for lubricating and cooling purposes.

[0004] Scroll compressors depend upon a number of seals to be created todefine the moving or successive chambers. One type of seal which must becreated are the seals between opposed flank surfaces of the wraps. Theseflank seals are created adjacent to the outer suction port and travelradially inward along the flank surface due to the orbiting movement ofone scroll with respect to the other scroll. Additionally sealing isrequired between the end plate of one scroll member and the tip of thewrap of the other scroll member. Because scroll compressors depend uponthe seals between flank surfaces of the wraps and the seals between theend plates and opposing wrap tips, suction and discharge valves aregenerally not required.

[0005] While the prior art scroll machines are designed to run troublefree for the life of the scroll machine, it is still necessary tomonitor the operation of the compressor and discontinue its operationwhen specific criteria have been exceeded. Typical operationalcharacteristics which are monitored include the discharge temperature ofthe compressed refrigerant, the temperature of the motor windings,three-phase reverse rotational protection, three-phase missingphase/single phase protection and an anti-short cycle. The monitoring ofthese characteristics and the methods and devices for monitoring thesecharacteristics have been the subject of numerous patents.

[0006] Recently, it has been found that by monitoring the vibrationalcharacteristics of the scroll machine, it is possible to predictproblems with a scroll machine before these problems result in a failureto the entire system. For instance, in a refrigeration or airconditioning system which incorporates numerous scroll machines, theabnormal vibration of one of the scroll machines can result in afracture of the refrigeration tube associated with that individualscroll machine. The fracture of this tube will result in a total loss ofthe system refrigerant, possible damage to property, expensive repairsand in some cases could be hazardous. Assignee's U.S. Pat. No.5,975,854, the disclosure of which is incorporated herein by reference,disclosed a device which is capable of independently monitoring thevibrational characteristics of an individual scroll machine.

[0007] Accordingly, what is needed is a system which is capable ofcommunicating with and monitoring the operational characteristics of acompressor and/or a group of compressors. The system should have theability to monitor all aspects of the operational characteristics ofeach of the compressor as well as having the ability to communicate witha central monitoring system to identify current or possible problemsassociated with the individual compressor. The central monitoring systemcan be a centralized rack gateway which communicates with eachindividual compressor, a rack/system control that acts as a gateway tocommunicate with each individual compressor or an Internet web serverthat communicates with a gateway associated with each compressor.

[0008] The present invention provides the art with an advancedcompressor control and protection system. The advanced compressorcontrol and protection system incorporates internally integratedsensing, protection and control functions not provided by the prior artmotor protection modules in use today. The control and protection systemof the present invention integrates these functions with the compressorfor improved overall system cost, reliability and value and thusprovides improved compressor protection, simpler system wiring,diagnostics and communications. The advanced compressor control andprotection system of the present invention provides a common hardwareplatform for a broad range of compressor modules. The system of thepresent invention provides a reduction in cost due to common electronicsplatform for all sensing and control functions, higher reliability dueto improved protection because of common logic incorporating amultiplicity of sensor and status information as well as reduction incost and improved reliability due to reduction in field wiring ofindividual stand-alone protection systems.

[0009] The present invention utilizes a low-cost communications enablingapproach using intermediate communications protocol to facilitate use ofadapters and gateways for virtually any communications network withminimal cost burden on non-network applications. Multiple sensors areadapted for use internally within the compressor which provide signalswhich are analogous to the actual physical quantities being measured.Examples are discharge temperature, motor winding temperatures, gaspressure (suction, discharge) and differential pressures, liquid level,liquid refrigerant, relative percentage of liquid refrigerant versus oiland others.

[0010] Other advantages and objects of the present invention will becomeapparent to those skilled in the art from the subsequent detaileddescription, appended claims and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The present invention will become more fully understood from thedetailed description and the accompanying drawings, wherein:

[0012]FIG. 1 is a vertical cross-sectional view through the center of ascroll type refrigeration compressor incorporating the control andprotection system in accordance with the present invention;

[0013]FIG. 2 is a top plan view of the compressor shown in FIG. 1;

[0014]FIG. 3 is a perspective view of the electrical enclosure shown inFIG. 2;

[0015]FIG. 4 is a side view of the compressor protection and controlsubsystem shown in FIG. 3;

[0016]FIG. 5 is a functional block diagram of the compressor protectionand control subsystem shown in FIG. 3;

[0017]FIG. 6 is a top plan view of the preferred implementation of thevibration sensor which can be incorporated into the compressorprotection and control subsystem shown in FIG. 4;

[0018]FIG. 7 is a side cross sectional view of the vibration sensorshown in FIG. 5;

[0019]FIG. 8 is a vertical cross-sectional view of a compressor having acapacity control system;

[0020]FIG. 9 is a vertical cross-sectional view of a compressor having aliquid injection system;

[0021]FIG. 10 is a plan cross-sectional view of a compressor having anoil injection system;

[0022]FIG. 11 is a schematic illustration of the gateway optionsavailable for the compressor;

[0023]FIG. 12 is a schematic representation of a control system for aplurality of compressors using various gateways;

[0024]FIG. 13 is a schematic representation of another control systemfor a plurality of compressors using various gateways;

[0025]FIG. 14 is a schematic representation of another control systemfor a plurality of compressors using various gateways;

[0026]FIG. 15 is an oil sensor used with the compressor;

[0027]FIG. 16 is another oil sensor used with the compressor; and

[0028]FIG. 17 is a functional block diagram of the compressor protectionand control subsystem for a semi-hermetic compressor.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] The following description of the preferred embodiment(s) ismerely exemplary in nature and is in no way intended to limit theinvention, its application, or uses.

[0030] Referring now to the drawings in which like reference numeralsdesignate like or corresponding parts throughout the several views,there is shown in FIGS. 1 and 2 a scroll compressor which incorporatesthe compressor protection and control subsystem in accordance with thepresent invention which is designated generally by reference numeral 10.While the compressor protection and control subsystem is beingillustrated for exemplary purposes in association with a hermetic scrollcompressor, it is within the scope of the present invention to use thecompressor protection and control subsystem with other rotarycompressors also. Compressor 10 comprises a generally cylindricalhermetic shell 12 having welded at the upper end thereof a cap 14 and atthe lower end thereof a base 16 having a plurality of mounting feet (notshown) integrally formed therewith. Cap 14 is provided with arefrigerant discharge fitting 18 which may have the usual dischargevalve therein (not shown). Other major elements affixed to the shellinclude a transversely extending partition 22 which is welded about itsperiphery at the same point that cap 14 is welded to shell 12, a mainbearing housing 24 which is suitably secured to shell 12, a lowerbearing housing 26 also having a plurality of radially outwardlyextending legs each of which is also suitably secured to shell 12 and anelectrical enclosure 28 (FIG. 2). A motor stator 30 which is generallysquare in cross-section but with the corners rounded off is press fittedinto shell 12. The flats between the rounded corners on the statorprovide passageways between the stator and shell, which facilitate thereturn flow of lubricant from the top of the shell to the bottom.

[0031] A drive shaft or crankshaft 32 having an eccentric crank pin 34at the upper end thereof is rotatably journaled in a bearing 36 in mainbearing housing 24 and a second bearing 38 in lower bearing housing 26.Crankshaft 32 has at the lower end a relatively large diameterconcentric bore 40 which communicates with a radially outwardly inclinedsmaller diameter bore 42 extending upwardly therefrom to the top ofcrankshaft 32. Disposed within bore 40 is a stirrer 44. The lowerportion of the interior shell 12 defines an oil sump 46 which is filledwith lubricating oil to a level slightly above the lower end of a rotor48, and bore 40 acts as a pump to pump lubricating fluid up thecrankshaft 32 and into passageway 42 and ultimately to all of thevarious portions of the compressor which require lubrication.

[0032] Crankshaft 32 is rotatively driven by an electric motor includingstator 30, windings 50 passing therethrough and rotor 48 press fitted onthe crankshaft 32 and having upper and lower counterweights 52 and 54,respectively.

[0033] The upper surface of main bearing housing 24 is provided with aflat thrust bearing surface 56 on which is disposed an orbiting scrollmember 58 having the usual spiral vane or wrap 60 on the upper surfacethereof. Projecting downwardly from the lower surface of orbiting scrollmember 58 is a cylindrical hub having a journal bearing 62 therein andin which is rotatively disposed a drive bushing 64 having an inner bore66 in which crank pin 32 is drivingly disposed. Crank pin 32 has a flaton one surface which drivingly engages a flat surface (not shown) formedin a portion of bore 66 to provide a radially compliant drivingarrangement, such as shown in assignee's U.S. Pat. No. 4,877,382, thedisclosure of which is hereby incorporated herein by reference. AnOldham coupling 68 is also provided positioned between orbiting scrollmember 58 and bearing housing 24 and keyed to orbiting scroll member 58and a non-orbiting scroll member 70 to prevent rotational movement oforbiting scroll member 58. Oldham coupling 68 is preferably of the typedisclosed in assignee's co-pending U.S. Pat. No. 5,320,506, thedisclosure of which is hereby incorporated herein by reference.

[0034] Non-orbiting scroll member 70 is also provided having a wrap 72positioned in meshing engagement with wrap 60 of orbiting scroll member58. Non-orbiting scroll member 70 has a centrally disposed dischargepassage 74 which communicates with an upwardly open recess 76 which inturn is in fluid communication with a discharge muffler chamber 78defined by cap 14 and partition 22. An annular recess 80 is also formedin non-orbiting scroll member 70 within which is disposed a sealassembly 82. Recesses 76 and 80 and seal assembly 82 cooperate to defineaxial pressure biasing chambers which receive pressurized fluid beingcompressed by wraps 60 and 72 so as to exert an axial biasing force onnon-orbiting scroll member 70 to thereby urge the tips of respectivewraps 60, 72 into sealing engagement with the opposed end platesurfaces. Seal assembly 82 is preferably of the type described ingreater detail in U.S. Pat. No. 5,156,539, the disclosure of which ishereby incorporated herein by reference. Non-orbiting scroll member 70is designed to be mounted to bearing housing 24 in a suitable mannersuch as disclosed in the aforementioned U.S. Pat. No. 4,877,382 or U.S.Pat. No. 5,102,316, the disclosure of which is hereby incorporatedherein by reference.

[0035] Referring now to FIG. 3, electrical enclosure 28 includes anelectrical case 84, a compressor protection and control subsystem 86 anda cover 88. Electrical case 84 is mounted to shell 12 using a pluralityof studs 90 (FIG. 2) which are resistance welded to shell 12. Compressorprotection and control subsystem 86 is mounted within electrical case 84using a pair of mounting screws 92. Compressor protection and controlsubsystem 86 is connected to the various components of compressor 10using wiring which has been omitted from the Figures for purposes ofclarity. The connections for compressor protection and control subsystem86 will be discussed in greater detail below. Compressor protection andcontrol subsystem 86 includes a status display 94 which indicates thestatus of protection and control subsystem 86 and thus the operatingstatus of compressor 10. Cover 88 is attached to electrical enclosure 84using a plurality of screws 98. Cover 88 defines an aperture 100 whichaligns with status display 94 to enable an individual to determine theoperating status of compressor 10 without having to remove cover 88.Status display 94 is capable of displaying numbers and some alphacharacters to indicate the various fault codes associated withcompressor protection and control subsystem 86.

[0036] Referring now to FIGS. 4 and 5, a side view of compressorprotection and control subsystem 86 is shown in FIG. 4 and a functionalblock diagram of compressor protection and control subsystem 86 is shownin FIG. 5. Compressor protection and control subsystem 86 includesstatus display 94 as well as terminals 102 through 136 some of which areconnected to internally integrated sensors which are in turn connectedto a control block 138. Terminals 102 and 104 are connected to a highpressure cut off switch 140 and a low pressure cut off switch 142through an isolated pressure switch sensing monitor 144. High pressurecut off switch 140 will notify compressor protection and controlsubsystem 86 of a higher than acceptable pressure reading for compressor10 and low pressure cut off switch 142 will notify compressor protectionand control subsystem 86 of a lower than acceptable pressure reading forcompressor 10.

[0037] Terminal 106 is connected to a pressure sensor 146 which monitorsthe discharge pressure of compressor 10. Terminal 108 is connected to apressure sensor 148 which monitors the suction pressure of compressor10. Terminal 110 is connected to a temperature sensor 15 0 whichmonitors the temperature of the discharge gas of compressor 10. Terminal112 is connected to an oil level sensor 152 which monitors the oil levelsump 46 of compressor 10. Input from sensors 146-152 are connected toterminals 106-112, respectively, through an analog to digital converter154 prior to being input to control block 138.

[0038] Terminals 114, 116, and 118 are connected to a first, a secondand a third phase wiring, 156-160, for compressor 10 in order to monitorthe status of the three-phase power supply for compressor 10. Wirings156-160 are connected to control block 138 and terminals 114-118 throughan isolation and signal conditioner 162. Terminals 120 and 122 areconnected to a group of motor temperature sensors 164 through a PTCInput circuit 166. Terminal 124 is connected to a compressor controlsystem 168 which indicates that all monitored systems are acceptable andcompressor 10 is free to operate.

[0039] Vibration detection can be added to compressor protection andcontrol subsystem 86 by incorporating a preferred vibration sensor 180within compressor protection and control subsystem 86 as shown in dashedlines in FIG. 4. Vibration sensor 180 is shown in FIGS. 6 and 7 and itcomprises a cover 182, a contractor ring 184, a terminal rod 186, aspring wire 188, a ball 190, and an end cap 192. Cover 182 is agenerally rectangular shaped plastic component defining a internalcircular bore 194. Contractor ring 184 is fit within an enlarged portionof bore 194 and rests against a shoulder 196 formed by bore 194.Terminal rod 186 extends through a side wall of cover 182. Terminal rod186 is welded to contractor ring 184 such that the end of terminal rod186 extending through cover 182 can be utilized as a solder point forvibration sensor 180.

[0040] Spring wire 188 is an L-shaped wire member which has one end ofthe L extending through the side wall of cover 182 and the opposite endof the L extending axially down the center line of circular bore 194such that the end of spring wire 188 terminates in approximately thecenter of contractor ring 184. Ball 190 includes a radially extendingbore 198 which extends from the outer surface of ball 190 toapproximately the center of ball 190. Preferably, ball 190 and springwire 188 are assembled by inserting spring wire 188 into bore 198 andapplying a strong permanent epoxy or by other methods known well in theart. The end of spring wire 188 which extends out of cover 182 is usedas a solder point for vibration sensor 180. End cap 192 is attached tocover 182 by use of a permanent set epoxy which seals bore 194 and thusprotects the electrical contacts of vibration sensor 180.

[0041] Preferably, spring wire 188 is made from spring quality steel ormusic wire, ball 190 is made form stainless steel (either 302 or 304)and contractor ring 184 is made from a seamless 304 stainless steelhollow tubular stock. Contractor ring 184 and ball 190 are preferablyplated with gold up to a thickness of 0.000015 inches to preventoxidation. In the preferred method of fabricating, spring wire 188 andcontractor ring 184 are molded in place. Ball 190 is then secure tospring wire 188 and then end cap 192 is assembled.

[0042] Ball 190 and spring wire 188 comprise a simple spring-masssystem. Spring wire 188 has the dual purpose of serving as oneelectrical terminal and also to act as the stiffness member of thespring-mass system. Vibration sensor 180 is located on the circuit boardfor compressor protection and control subsystem 86 and is most sensitiveto vibration in the plane which is perpendicular to the long axis ofvibration sensor 180 or the long axis of spring wire 188. Sensor 180 isactually a form of electrical switch which requires a minimumdisplacement before the momentary circuit closures or pulses begin toappear. A sensor input network block includes an RC filter which reducesthe noise content of the signal.

[0043] In a given orientation, the response of vibration sensor 180 isgoverned by the stiffness of spring wire 188 and the mass of ball 190.System response is measured in terms of the amplitude of oscillations ofball 190 when vibration sensor 180 is attached to compressor 10. Inprinciple, sensor 180 is designed to have a natural frequency close tothe operating frequency of compressor 10. Preferably the naturalfrequency of sensor 180 is maintained on the higher side of theoperating frequency of compressor 10 to eliminate nuisance trips. Bycontrolling parameters such as the stiffness of spring wire 188, themass of ball 190 and the gap between ball 190 and contractor ring 184,it is possible to design sensor 180 to trigger only above a specificvalue of input vibration. In this context, triggering is said to occurwhen ball 190 contacts ring 184. The stiffness of spring wire 188 is afunction of the diameter, length and material of spring wire 188, themass of ball 190 is a function of its material and its diameter. Thus,by making variations in these parameters, it is possible to change theresponse curve of sensor 180. The sensitivity of sensor 180 isdetermined by the gap between ball 190 and contact ring 184 and howclose the natural frequency of sensor 180 is to the operating frequencyof compressor 10. If the two frequencies are close, the system may beover sensitive; i.e. a small change in input vibration amplitude willresult in a significant change in output vibration of movement of ball190. Similarly, if the two frequencies are far apart, the system may beunder sensitive and require a larger input vibration amplitude to causea small change in output vibration or movement of ball 190. Computerstudies and parallel experimental work has determined that a preferredsensor 180 will trigger at input signal levels of 10-15 mils of inputvibration. This preferred design is insensitive to input vibration under8 mils.

[0044] One issue which needs to be addressed with vibration sensor 180is it must have the ability to distinguish between a true excessivevibration condition and the normal transient vibrations experiencedduring start up, flooded start, shut down and the like. Compressorprotection and control subsystem module 86 preferably includes a firstcounter which continuously counts any pulses or triggering that arepresent using a 10 second time interval. If the number of pulses countedduring any 10 second interval exceeds a predetermined number, a limitcondition flag is turned on. Conversely, if the number of pulses countedduring any 10 second interval is less than a predetermined number, thelimit condition flag is turned off. Compressor protection and controlsubsystem 86 implements a second counter which is an up-down counter. Itis clocked by an internal 1 second clock. The counter is limited to 0counts in the down direction and 120 counts in the up direction. If thecondition limit flag is turned on, the counter counts up. If the limitcondition flag is turned off, the counter counts down. If at any timethe count reaches 120, control and protection module 86 turns off thecontrol relay and sets status display 94 to indicate a “vibration tripcondition”. Recycling of power to compressor protection and controlsubsystem 86 is required to clear this condition and reset the counterto 0.

[0045] Control block 138 of compressor protection and control subsystem86 can also be used to control other various and perhaps optionalsystems incorporated into compressor 10. Terminal 126 is designed to beconnected to a solenoid control system 210 which in turn is connected toan unloading control for a compressor for controlling the capacity of acompressor 214 shown in FIG. 8. Compressor 214 is identical tocompressor 10 except for the incorporation of a capacity control system216 which is controlled by control block 138.

[0046] Terminal 128 is designed to be connected to a solenoid controlsystem 218 which is, in turn, connected to a liquid injection system 222for controlling the liquid injection for a compressor 224 shown in FIG.9. Compressor 224 is identical to compressor 10 except for theincorporation of liquid injection system 222.

[0047] Terminal 130 is designed to be connected to a solenoid controlsystem 226 which is, in turn, connected to an oil injection system 230for controlling oil injection for a compressor 234 shown in FIG. 10.Compressor 234 is identical to compressor 10 except for theincorporation of oil injection system 230.

[0048] Terminal 132 is designed to be connected to a heater controlsystem 236 which is, in turn, connected to a crankcase heater 238 forheating the lubricating oil in sump 46 of compressor 10 as shown in FIG.1.

[0049] While FIGS. 8-10 each show a separate system added to compressor10, it is within the scope of the present invention to include one ormore of systems 216, 222 or 230 if desired.

[0050] Communication with control block 138 of compressor protection andcontrol subsystem 86 is provided by a communication interface or gateway250 which communicates with control block 138 through terminals 134 and136. DC voltage to power the various sensors is provided a power supplysystem 252. Gateway 250 uses Motorola's Serial Peripheral Interface(SPI) for communicating with bridge or gateway modules. Motorola's SPIwas designed to allow communications between a microcontroller andintegrated circuits on a board providing expanded peripheral functions.Another bus, the I²C is similar to the SPI and was developed bySignetics/Philips Semiconductor. By using one of these buses, the onlyhardware required for connection to a pluggable gateway board is asuitable connector. By taking this approach, the system communicationsprotocol is limited only by the gateways made available.

[0051] The SPI and I²C are the lowest cost approaches to providingcommunications and all that is needed is an adapter or a gateway. Thepreferred embodiment uses a serial interface using RS-485. The protocolused by the advanced compressor control and protection system of thepresent invention for either the simple SPI-to-gateway communications orin the case of an RS-485 based local network application is amaster-slave protocol. The system control is the master when the localRS-485 interface is used. If another protocol is required, the gatewaymodule acts as the master on the compressor control interface side.

Node Address Assignments

[0052] There are 32 node addresses to specify the target node. Address 0is reserved for master broadcast messages. Address 31 is reserved formessages to the bus master. The remaining addresses are available forslave nodes. The Node Address is contained in the five most significantbits of Byte 0.

Message Types

[0053] The message type is contained in the least significant three bitsof Byte 0. Eight message types are defined as follows:

[0054] 1. Slave Status Request—This message is used by the system masterto interrogate a slave node for its status. The addressed slave respondswith one or more Status Reply messages. This message has a packet lengthof zero (0).

[0055] 2. Status Reply—This message is used by slave nodes as a reply toSlave Status Request messages from the system master.

[0056] 3. Control Commands—A Command Control message is used to controlthe actuator outputs of a slave node. Packet zero (0) of this messagetype is always a single byte and is used as a hardware reset command.All bits set to 1's generate a hardware reset in the slave node.

[0057] 4. Configuration Request—The Configuration Read message is usedby the system master to command a slave node to send its configurationdata by means of one or more data packets contained in ConfigurationData messages. This message has a packet length of zero (0).

[0058] 5. Configuration Data—The Configuration Data message is used tosend data packets containing the slave node's configuration data whenthe slave node has received a Configuration Read message. This istypically data stored in the slave node's EEROM of Flash Memory storage.It causes information which identifies the node type, serial number,date of manufacture, event histories, etc.

[0059] 6. Sensor Read Request—The Sensor Read message is sent by thesystem master to command the slave node to send its sensor data. Thismessage has a packet length of zero (0).

[0060] 7. Sensor Data—This message type is sent by a slave node inresponse to the Sensor Read message from the system master.

[0061] 8. Receipt Response—The Receipt Response message is sent by aslave node in response to messages from the system master which do notrequire data to be returned. This data packet is always a 1 byte ACK orNAK.

[0062] Packet Number

[0063] A message type may have up to 8 packets. Each packet may be 1 to32 bytes in length and is sent in a separate message. The first messagesent has the packet number set to the number of packets to be sent. Eachsubsequent message has the packet number decremented. The last messagecontains the last packet to be sent and is packet number zero (0).

[0064] The packet Number is contained in the most significant 3 bits ofByte 1.

Packet Length

[0065] The Packet Length specifies the length of the Data Packet in eachmessage. The Packet Length is contained in the least significant 5 bitsof Byte 1. Each message contains a data packet with up to 31 data bytes.The only exception is a packet length of zero (0) bytes. In this casethere is no data packet in the message.

Node Types

[0066] Node definitions can be created for any component in a systemthat is capable of supporting communications. A good example would be arefrigeration case control. Or if partitioning of the system is desired,node definitions for individual or groups of sensors and actuators wouldmake sense. These definitions would define the specific messages andtheir content as required for the particular devices. This documentrelease focuses on the compressor node only.

Compressor Node

[0067] The compressor node utilizes all message types available. TheConfiguration data message type 5 is used to transfer the compressorconfiguration data between the system master and each compressor node.The compressor is shipped with the data preconfigured. The system mastermay send a Configuration Request to a selected compressor node and getan image of the stored data. It may modify that data or it may constructa completely new image and send it to the compressor for storage bysending it in the appropriate series of Configuration Data packets.Typical configuration variables are listed below.

Configuration Data List

[0068] Compressor Information

[0069] Compressor Model Code

[0070] Compressor Serial Number

[0071] Application

[0072] Application Temperature Range

[0073] Refrigerant Code

[0074] Oil Code

[0075] Oil Charge

[0076] Customer Information

[0077] Customer Name

[0078] Customer Model Number

[0079] Control Configuration

[0080] Anti Short Cycle Time

[0081] Discharge Pressure Cut-in

[0082] Discharge Pressure Cut-out

[0083] Discharge Pressure Sensor Option Enabled

[0084] Discharge Trip Time

[0085] Discharge Multiplier

[0086] Discharge Divider

[0087] Discharge Temperature Cut-out

[0088] Oil Add Set Point

[0089] Oil Stop Add Set Point

[0090] Oil Trip Set Point

[0091] Oil On Time

[0092] Oil Off Time

[0093] Oil Add Period

[0094] Shake Limit (pulses/10 second period.)

[0095] Shake Count (number of periods)

[0096] Suction Pressure Low Limit

[0097] Suction Pressure High Limit

[0098] Suction Multiplier

[0099] Suction Divider

[0100] Suction Pressure Sensor Option

[0101] Additional information in the Configuration Data category iscertain history information as listed below.

[0102] Event History

[0103] Compressor Cycles

[0104] Compressor On Time

[0105] Discharge Pressure Trips

[0106] Discharge Temperature

[0107] Motor Trips

[0108] Oil Trips

[0109] Suction Pressure Limit Trips

[0110] Shake Limit Trips

[0111] Events Since Cleared

[0112] Using the above described protocol, some typical sensor datawhich would be sent in response to a sensor data request would be asdetailed below.

[0113] Anti Short Cycle Time—32 bit unsigned (mS)

[0114] Discharge Pressure Cut-in—32 bit signed (up to 6553.5 kPa, res.0.1 kPa)

[0115] Discharge Pressure Cut-out—32 bit signed (up to 6553.5 kPa, res.0.1 kPa)

[0116] Discharge Trip Time—16 bit unsigned (res. 0.01 S)

[0117] Discharge Multiplier—32 bit unsigned

[0118] Discharge Divider—32 bit unsigned

[0119] Suction Pressure Cut-in—32 bit signed (+,−3276.7 kPa, res. 0.1kPa)

[0120] Oil Stop Add—16 bit unsigned

[0121] Suction Pressure Cut-out—32 bit signed (+,−3276.7 kPa, res. 0.1kPa)

[0122] Suction Multiplier—32 bit unsigned

[0123] Suction Divider—32 bit unsigned

[0124] Oil Add—16 bit unsigned

[0125] Oil Trip—16 bit unsigned

[0126] Oil On Time—32 bit unsigned (mS)

[0127] Oil Off Time—32 bit unsigned (mS)

[0128] Oil Add Period—16 bit unsigned (0.01 S)

[0129] Vibration Limit—16 bit unsigned—pulses/10 s

[0130] Vibration Count—8 bit unsigned—10 s periods

[0131] Referring now to FIG. 11, compressor 10 is illustrated showingthe Serial Peripheral Interface (SPI) for connecting compressorprotection and control subsystem 86 of compressor 10 to a centralcontrol system 254. Using the SPI interface and the gateway, subsystem86 of compressor 10 can be controlled by and communicate with a masternetwork. The connection and communication with the master network ispreferably through LonWorks but other network connections such as SPi,CANBus, Device Net, Internet/intranet, BAC net or a Proprietaryconnection can be established. FIG. 12 illustrates the network systemwhen a centralized rack gateway 256 is utilized to communicate with agroup of compressors 10, FIG. 13 illustrates the network system when arack/system control 258 acts as the gateway for communicating with agroup of compressors 10 and FIG. 14 illustrates the network system whenan Internet web server 260 or a local Intranet server 262 is utilized tocommunicate with individual Ethernet gateways associated with eachcompressor 10.

[0132] One problem associated with the development of the advancedcompressor control and protection system was an accurate oil levelsensor applicable to compressors. The requirements for the sensorincluded that it have no moving parts, that it be compatible with theenvironment of the interior of the compressor in the sump and that itscosts be competitive with current day float based sensors. Two conceptswere deemed to have merit. First, self-heated thermistor withtemperature compensation had the potential to be simple, reliable andlow cost and second, capacitance was considered as a potentiallyreliable, accurate and low cost approach as well.

[0133] A capacitance based sensor 300 shown in FIG. 15 is one option foran oil sensor. There is a large enough dielectric constant of oil versusrefrigerant gas to be able to derive a usable signal. The volumeconstruction of such a device having a consistent capacitance from unitto unit without calibration is feasible if the electrodes are arrangedcoaxially. Sensor 300 is comprised of a hollow stainless tube 302 with asmall coaxially positioned rod 304.

[0134] A multiple thermocouple liquid level sensor 320 is shown in FIG.16. Sensor 320 comprises an unevenly heated thermocouple array 322.Sensor 320 requires a compensation for the effect of different gasdensities by using a separate unevenly heated thermocouple pair which isalways disposed within the suction gas of the compressor. A mathematicalmodel was developed using the output from the thermocouple disposed inthe gas to correct the output of the thermocouple disposed in thelubricant for variation pressure and temperature of the suction gas overthe compressor's operating envelope.

[0135] Referring now to FIG. 17, a system schematic for a compressorprotection and control subsystem 86′ for use with a semi-hermetic rotarycompressor is disclosed. Subsystem 86′, shown in FIG. 17, is similar tosubsystem 86 shown in FIG. 5 except for the addition of control for anoil switch 300. A semi-hermetic rotary compressor is similar to ahermetic rotary compressor except that the shell for the semi-hermeticrotary compressor is bolted together rather than being welded as shownfor shell 12. in addition, the semi-hermetic rotary compressor istypically equipped with a positive displacement lubricant pump whichmaintains an oil pressure within the lubrication system for thesemi-hermetic rotary compressor. A pressure sensor monitors the pressurefor the lubrication system with the pressure sensor communicating withcontrol block 138 through a pair of terminals 302 and 304. Logic withincontrol block 138 monitors the lubrication after lubrication pressure isdetermined to be low or inadequate for a specified period of time. Thetime delay used for controlling the compressor for a lack of sufficientoil pressure avoids problems associated with mis-trips caused to varyingoil pressure. The function and operation of the remainder of compressorprotection and control subsystem 86′ is the same as that described abovefor compressor protection and control subsystem 86.

[0136] While the above detailed description describes the preferredembodiment of the present invention, it should be understood that thepresent invention is susceptible to modification, variation andalteration without deviating from the scope and fair meaning of thesubjoined claims.

What is claimed is:
 1. A cooling system comprising: a compressor rackincluding a plurality of compressors; a controller dedicated to eachcompressor of said plurality of compressors, each controller including amemory operable to store configuration data specific to said compressor,said configuration data including data identifying said compressor andproviding compressor operating units; and; a system master operable tocommand each said controller to send said configuration data to saidsystem master, said system master operable to store a copy of saidconfiguration data for each said compressor.
 2. The cooling system ofclaim 1, wherein said system master is operable to command each saidcontroller to send said configuration data to said system master.
 3. Thecooling system of claim 1, wherein said system master is operable tomodify said configuration data.
 4. The cooling system of claim 1,wherein said system master is operable to send new configuration data toeach said controller.
 5. The cooling system of claim 1, wherein saidcontroller includes a microprocessor.
 6. The cooling system of claim 1,wherein said microprocessor functions as a communication gateway forcommunicating with said system master.
 7. The cooling system of claim 1,wherein said configuration data includes at least one or more of thegroup comprising: compressor information, compressor model code,compressor serial number, application, application temperature range,refrigerant code, oil code, oil charge, customer information, customername, customer model number, control configuration, anti-short cycletime, discharge pressure cut-in, discharge pressure cut-out, dischargepressure sensor option enabled, discharge trip time, dischargemultiplier, discharge divider, discharge temperature cut-out, oil addset point, oil stop add set point, oil trip set point, oil on time, oiloff time, oil add period, shake limit, shake count, suction pressure lowlimit, suction pressure high limit, suction multiplier, suction divider,suction pressure sensor option, event history, compressor cycles,compressor on time, discharge pressure trips, discharge temperature,motor trips, oil trips, suction pressure limit trips, shake limit trips,events since cleared.
 8. The cooling system of claim 1, wherein saidsensor data includes at least one or more from the group comprising:anti-short cycle time, discharge pressure cut-in, discharge pressurecut-out, discharge trip time, discharge multiplier, discharge divider,suction pressure cut-in, oil stop add, suction pressure cut-out, suctionmultiplier, suction divider, oil add, oil trip, oil on time, oil offtime, oil add period, vibration limit, vibration count.
 9. A coolingsystem comprising: a first compressor; a first controller includingfirst configuration data for said first compressor; a first sensorassociated with said first compressor; a second compressor; a secondcontroller including second configuration data for said secondcontroller; a second sensor associated with said second compressor; anda system master in communication with said first controller and saidsecond controller, said system master operable to interrogate a statusof said first controller and said second controller, said system masteroperable to command said first controller and second controller to sendsaid first configuration data and said second configuration data to saidsystem master, and said system master operable to command said firstcontroller and said second controller to send said first sensor data andsaid second sensor data.
 10. The cooling system of claim 9, wherein saidsystem master is operable to command said first or second controller tosend said first or second sensor data, respectively, to said systemmaster.
 11. The cooling system of claim 9, wherein said system master isoperable to modify said configuration data.
 12. The cooling system ofclaim 9, wherein said system master is operable to send newconfiguration data to said first and second controllers.
 13. The coolingsystem of claim 9, wherein said first and second controllers includemicroprocessors.
 14. The cooling system of claim 13, wherein saidmicroprocessors function as a gateway for communicating with said systemmaster.
 15. The cooling system of claim 9, wherein said configurationdata includes at least one or more of the group comprising: compressorinformation, compressor model code, compressor serial number,application, application temperature range, refrigerant code, oil code,oil charge, customer information, customer name, customer model number,control configuration, anti-short cycle time, discharge pressure cut-in,discharge pressure cut-out, discharge pressure sensor option enabled,discharge trip time, discharge multiplier, discharge divider, dischargetemperature cut-out, oil add set point, oil stop add set point, oil tripset point, oil on time, oil off time, oil add period, shake limit, shakecount, suction pressure low limit, suction pressure high limit, suctionmultiplier, suction divider, suction pressure sensor option, eventhistory, compressor cycles, compressor on time, discharge pressuretrips, discharge temperature, motor trips, oil trips, suction pressurelimit trips, shake limit trips, events since cleared.
 16. The coolingsystem of claim 9, wherein said sensor data includes at least one ormore from the group comprising: anti-short cycle time, dischargepressure cut-in, discharge pressure cut-out, discharge trip time,discharge multiplier, discharge divider, suction pressure cut-in, oilstop add, suction pressure cut-out, suction multiplier, suction divider,oil add, oil trip, oil on time, oil off time, oil add period, vibrationlimit, vibration count.
 17. A compressor comprising: a housing; a fluidcompression mechanism disposed in said housing; a motor driving saidfluid compression mechanism; a controller disposed on said housing andincluding a memory and a communication gateway, said memory storingconfiguration data specific to the compressor, said configuration dataidentifying said compressor and providing compressor operating limits,said communication gateway operable to communicate with a system masterand allow said memory to be copied, modified, or replaced under thecontrol of the system master.
 18. The compressor of claim 17, whereinsaid controller sends said configuration data to the system masterthrough said gateway.
 19. The compressor of claim 17, wherein saidcontroller includes a microprocessor.
 20. The compressor of claim 19,wherein said microprocessor functions as said communication gateway. 21.The compressor of claim 17, wherein said configuration data includes atleast one or more of the group comprising: compressor information,compressor model code, compressor serial number, application,application temperature range, refrigerant code, oil code, oil charge,customer information, customer name, customer model number, controlconfiguration, anti-short cycle time, discharge pressure cut-in,discharge pressure cut-out, discharge pressure sensor option enabled,discharge trip time, discharge multiplier, discharge divider, dischargetemperature cut-out, oil add set point, oil stop add set point, oil tripset point, oil on time, oil off time, oil add period, shake limit, shakecount, suction pressure low limit, suction pressure high limit, suctionmultiplier, suction divider, suction pressure sensor option, eventhistory, compressor cycles, compressor on time, discharge pressuretrips, discharge temperature, motor trips, oil trips, suction pressurelimit trips, shake limit trips, events since cleared.
 22. The compressorof claim 17, wherein said sensor data includes at least one or more fromthe group comprising: anti-short cycle time, discharge pressure cut-in,discharge pressure cut-out, discharge trip time, discharge multiplier,discharge divider, suction pressure cut-in, oil stop add, suctionpressure cut-out, suction multiplier, suction divider, oil add, oiltrip, oil on time, oil off time, oil add period, vibration limit,vibration count.